Crustal Accretion and Mantle Geodynamics at Microplates: Constraints from Gravity Analysis and Numerical Modeling ...

• Main Author: Ames, Katherine
• Format: Text
• Language: unknown
• Published: Old Dominion University 2014
• Subjects: Antarc*; Antarctic
• Online Access: https://dx.doi.org/10.25777/cydb-w518; https://digitalcommons.odu.edu/oeas_etds/343/

This study investigates crustal accretion and mantle geodynamics at microplates using mantle Bouguer anomaly (MBA) gravity calculations and exploratory numerical models. The Easter and Juan Fernandez microplates are located in the eastern Pacific Ocean along the Pacific, Nazca, and Antarctic plate boundaries. Both microplates formed 3-5 Ma and they are currently rotating clockwise at 15° myr-1 and 9° myr-1,respectively [ e.g., Searle et al., 1993]. The study area also encompasses the Easter /Salas y Gomez mantle plume located near the Easter microplate. Both microplates show a difference in average MBA between their west and east ridges, with the west ridges having more negative MBA values than the eastern ones. This is consistent with the east ridges rifting into cooler, older lithosphere. The thermal effect of the Easter/Salas y Gomez plume calculated by comparing MBA along the Easter microplate east and west rifts was minimal (~10°C); however, the cooler lithosphere on the east ridge may mask the hotspot ...